Selection Pressure Profile Suggests Species Criteria among Tick-Borne Orthoflaviviruses.

Orthoflaviviruses are arthropod-borne viruses that are transmitted by mosquitoes or ticks and cause a range of significant human diseases. Among the most important tick-borne orthoflaviviruses (TBFVs) is tick-borne encephalitis virus (TBEV), which is endemic in Eurasia, and Powassan virus, which is endemic in Asia and North America. There is a significant controversy regarding species assignment in the tick-borne encephalitis virus complex due to the complex phylogenetic, serological, ecological, and pathogenetic properties of viruses.

Detection of Polioviruses Type 2 among Migrant Children Arriving to the Russian Federation from a Country with a Registered Poliomyelitis Outbreak.

The widespread use of the oral poliovaccine from Sabin strains (tOPV) radically reduced poliomyelitis incidence worldwide. However, OPV became a source of neurovirulent vaccine-derived polioviruses (VDPVs). Currently, circulating type 2 VDPVs (cVDPV2) are the leading cause of poliomyelitis.

An Integrative Approach to the Study of Cognitive Abilities in a Non-Human Primate Model in a Virology Laboratory Environment.

Non-human primates, due to their similarities in immune response to humans, are the preferred model for studying infectious processes and any associated cognitive impairments. Behavioral tests are indispensable for investigating pathogenesis in neuroinfections, especially those that do not manifest with noticeable clinical symptoms, as well as in the transition to a chronic form of the disease. Modeling viral infection requires specialized experimental conditions.

Phenotypic assessment of antiviral activity for spiro-annulated oxepanes and azepenes.

Evolutionary potential of viruses can result in outbreaks of well-known viruses and emergence of novel ones. Pharmacological methods of intervening the reproduction of various less popular, but not less important viruses are not available, as well as the spectrum of antiviral activity for most known compounds. In the framework of chemical biology paradigm, characterization of antiviral activity spectrum of new compounds allows to extend the antiviral chemical space and provides new important structure-activity relationships for data-driven drug discovery.

High-Throughput Sequencing Reveals Three Rhabdoviruses Persisting in the IRE/CTVM19 Cell Line.

Cell cultures derived from ticks have become a commonly used tool for the isolation and study of tick-borne pathogens and tick biology. The IRE/CTVM19 cell line, originating from embryos of , is one such line. Previously, reovirus-like particles, as well as sequences with similarity to rhabdoviruses and iflaviruses, were detected in the IRE/CTVM19 cell line, suggesting the presence of multiple persisting viruses.

The structure of inactivated mature tick-borne encephalitis virus at 3.0 Å resolution.

Tick-borne encephalitis virus (TBEV) causes a severe disease, tick-borne encephalitis (TBE), that has a substantial epidemiological importance for Northern Eurasia. Between 10,000 and 15,000 TBE cases are registered annually despite the availability of effective formaldehyde-inactivated full-virion vaccines due to insufficient vaccination coverage, as well as sporadic cases of vaccine breakthrough. The development of improved vaccines would benefit from the atomic resolution structure of the antigen.

Non-Polio Enteroviruses Isolated by Acute Flaccid Paralysis Surveillance Laboratories in the Russian Federation in 1998-2021: Distinct Epidemiological Features of Types.

More than 100 types of non-polio enteroviruses (NPEVs) are ubiquitous in the human population and cause a variety of symptoms ranging from very mild to meningitis and acute flaccid paralysis (AFP). Much of the information regarding diverse pathogenic properties of NPEVs comes from the surveillance of poliovirus, which also yields NPEV. The analysis of 265 NPEV isolations from 10,433 AFP cases over 24 years of surveillance and more than 2500 NPEV findings in patients without severe neurological lesions suggests that types EV-A71, E13, and E25 were significantly associated with AFP.

Preparation and characterization of inactivated tick-borne encephalitis virus samples for single-particle imaging at the European XFEL.

X-ray imaging of virus particles at the European XFEL could eventually allow their complete structures to be solved, potentially approaching the resolution of other structural virology methods. To achieve this ambitious goal with today's technologies, about 1 ml of purified virus suspension containing at least 10 particles per millilitre is required. Such large amounts of concentrated suspension have never before been obtained for enveloped viruses.

Inapparent Tick-Borne Orthoflavivirus Infection in : A Model for Antiviral Drug and Vaccine Research.

Tick-borne encephalitis virus (TBEV) and Powassan virus (POWV) are neurotropic tick-borne orthoflaviviruses. They cause mostly asymptomatic infections in hosts, but severe forms with CNS involvement can occur. Studying the early stages of viral infections in humans is challenging, and appropriate animal models are essential for understanding the factors determining the disease severity and for developing emergency prophylaxis and treatment options.

Structural diversity of tick-borne encephalitis virus particles in the inactivated vaccine based on strain Sofjin.

The main approach to preventing tick-borne encephalitis (TBE) is vaccination. Formaldehyde-inactivated TBE vaccines have a proven record of safety and efficiency but have never been characterized structurally with atomic resolution. We report a cryoelectron microscopy (cryo-EM) structure of the formaldehyde-inactivated TBE virus (TBEV) of Sofjin-Chumakov strain representing the Far-Eastern subtype.

Recombinant TBEV Protein E of the Siberian Subtype Is a Candidate Antigen in the ELISA Test System for Differential Diagnosis.

The tick-borne encephalitis virus (TBEV) is one of the most common members of the genus, which comprises the causative agents of severe diseases in humans and animals. Due to the expanding areas of orthoflavivirus infection, its differential diagnosis is highly demanded. Commercial test kits based on inactivated TBEV may not provide reliable differentiation between flaviviruses because of serological crossover in this genus.

Development Features of × Hybrids under Laboratory Conditions.

Widely distributed and ticks transmit many pathogens of both medical and veterinary significance. The ranges of these tick species overlap and form large sympatric areas in the East European Plain and Baltic countries. It has previously been shown that crossing and is possible, resulting in the appearance of sterile hybrids.

3-[-Bis(sulfonyl)amino]isoxazolines with Spiro-Annulated or 1,2-Annulated Cyclooctane Rings Inhibit Reproduction of Tick-Borne Encephalitis, Yellow Fever, and West Nile Viruses.

Spirocyclic compounds containing heterocyclic moieties represent promising 3D scaffolds for modern drug design. In the search for novel anti-flaviviral agents, we have obtained a series of 3-[-bis(sulfonyl)amino]isoxazolines containing spiro-annulated cyclooctane rings and assessed their antiviral activity against tick-borne encephalitis (TBEV), yellow fever (YFV), and West Nile (WNV) viruses. The structural analogs of spirocyclic compounds with a single sulfonyl group or 1,2-annulated cyclooctane ring were also investigated.

Tetrahydroquinazoline N-oxide derivatives inhibit reproduction of tick-borne and mosquito-borne flaviviruses.

Tick-borne encephalitis virus (TBEV), yellow fever virus (YFV), and West Nile virus (WNV) are flaviviruses causing emerging arthropod-borne infections of a great public health concern. Clinically approved drugs are not available to complement or replace the existing vaccines, which do not provide sufficient coverage. Thus, the discovery and characterization of new antiflaviviral chemotypes would advance studies in this field.

Charge-changing point mutations in the E protein of tick-borne encephalitis virus.

Introduction of point mutations is one of the forces enabling arboviruses to rapidly adapt in a changing environment. The influence of these mutations on the properties of the virus is not always obvious. In this study, we attempted to clarify this influence using an in silico approach.

Activation of Early Proinflammatory Responses by TBEV NS1 Varies between the Strains of Various Subtypes.

Tick-borne encephalitis (TBE) is an emerging zoonosis that may cause long-term neurological sequelae or even death. Thus, there is a growing interest in understanding the factors of TBE pathogenesis. Viral genetic determinants may greatly affect the severity and consequences of TBE.

5-(Perylen-3-ylethynyl)uracil as an antiviral scaffold: Potent suppression of enveloped virus reproduction by 3-methyl derivatives in vitro.

Amphipathic nucleoside and non-nucleoside derivatives of pentacyclic aromatic hydrocarbon perylene are known as potent non-cytotoxic broad-spectrum antivirals. Here we report 3-methyl-5-(perylen-3-ylethynyl)-uracil-1-acetic acid and its amides, a new series of compounds based on a 5-(perylen-3-ylethynyl)-uracil scaffold. The compounds demonstrate pronounced in vitro activity against arthropod-borne viruses, namely tick-borne encephalitis virus (TBEV) and yellow fever virus (YFV), in plaque reduction assays with EC values below 1.

Dermacentor reticulatus - a tick on its way from glacial refugia to a panmictic Eurasian population.

The ornate dog tick (Dermacentor reticulatus) shows a recently expanding geographic distribution. Knowledge on its intraspecific variability, population structure, rate of genetic diversity and divergence, including its evolution and geographic distribution, is crucial to understand its dispersal capacity. All such information would help to evaluate the potential risk of future spread of associated pathogens of medical and veterinary concern.

Size Distribution of Inactivated Tick-Borne Encephalitis Virus Particles Revealed by a Comprehensive Physicochemical Approach.

Tick-borne encephalitis virus (TBEV) is an enveloped RNA virus, a member of the genus (family ). Here, we provide a detailed analysis of the size and structure of the inactivated TBEV vaccine strain Sofjin-Chumakov. Four analytical methods were used to analyze individual TBEV particles-negative staining TEM, cryo-EM, atomic force microscopy (AFM), and nanoparticle tracking analysis (NTA).

Pathogens in Ixodes persulcatus and Ixodes ricinus ticks (Acari, Ixodidae) in Karelia (Russia).

Ixodid ticks (Acarina, Ixodidae) are vectors of dangerous human infections. The main tick species that determine the epidemiological situation for tick-borne diseases in northern Europe are Ixodes ricinus and Ixodes persulcatus. In recent years, significant changes in the number and distribution of these species have been observed, accompanied by an expansion of the sympatric range.

Inactivated tick-borne encephalitis vaccine elicits several overlapping waves of T cell response.

The development and implementation of vaccines have been growing exponentially, remaining one of the major successes of healthcare over the last century. Nowadays, active regular immunizations prevent epidemics of many viral diseases, including tick-borne encephalitis (TBE). Along with the generation of virus-specific antibodies, a highly effective vaccine should induce T cell responses providing long-term immune defense.

[Viral meningoencephalitis with damage to the right temporal lobe with a favorable outcome].

Herpes simplex virus (HSV) is the most commonly identified cause of infectious meningoencephalitis in Western countries. Previous studies showed that neurological defects can form during HSV meningoencephalitis, ranging from symptomatic epilepsy to mental and movement disorders. The recovery of Cognitive Mental Functions (CMF) in a patient who survived HSV meningoencephalitis was evaluated.

Cytotoxicity reduction by O-nicotinoylation of antiviral 6-benzylaminopurine ribonucleosides.

One of the promising approaches in the development of nucleoside prodrugs is to use the nucleoside analogs containing lipophilic biodegradable residues, which are cleaved to biologically active forms after metabolic transformations in the cell. The introduction of such fragments makes it possible to reduce the general toxicity of the drug candidate and increase its stability in the cell. In order to study the influence of biodegradable lipophilic groups on antiviral activity and cytotoxicity, in this work we synthesized N-benzyl-2',3',5'-tri-O-nicotinoyl adenosine and N-(3-fluorobenzyl)-2',3',5'-tri-O-nicotinoyl adenosine, derivatives of N-benzyladenosine (BAR) and N-(3-fluorobenzyl)adenosine (FBAR), which had previously shown prominent antiviral activity against human enterovirus EV-A71 but appeared to be cytotoxic.